<?php
//
//  FPDI - Version 1.2
//
//    Copyright 2004-2007 Setasign - Jan Slabon
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

if (!defined ('PDF_TYPE_NULL'))
define ('PDF_TYPE_NULL', 0);
if (!defined ('PDF_TYPE_NUMERIC'))
define ('PDF_TYPE_NUMERIC', 1);
if (!defined ('PDF_TYPE_TOKEN'))
define ('PDF_TYPE_TOKEN', 2);
if (!defined ('PDF_TYPE_HEX'))
define ('PDF_TYPE_HEX', 3);
if (!defined ('PDF_TYPE_STRING'))
define ('PDF_TYPE_STRING', 4);
if (!defined ('PDF_TYPE_DICTIONARY'))
define ('PDF_TYPE_DICTIONARY', 5);
if (!defined ('PDF_TYPE_ARRAY'))
define ('PDF_TYPE_ARRAY', 6);
if (!defined ('PDF_TYPE_OBJDEC'))
define ('PDF_TYPE_OBJDEC', 7);
if (!defined ('PDF_TYPE_OBJREF'))
define ('PDF_TYPE_OBJREF', 8);
if (!defined ('PDF_TYPE_OBJECT'))
define ('PDF_TYPE_OBJECT', 9);
if (!defined ('PDF_TYPE_STREAM'))
define ('PDF_TYPE_STREAM', 10);


class pdf_parser {

	/**
	 * Filename
	 * @var string
	 */
	var $filename;

	/**
	 * File resource
	 * @var resource
	 */
	var $f;

	/**
	 * PDF Context
	 * @var object pdf_context-Instance
	 */
	var $c;

	/**
	 * xref-Data
	 * @var array
	 */
	var $xref;

	/**
	 * root-Object
	 * @var array
	 */
	var $root;

	// mPDF 4.0 Added flag to show success on loading file
	var $success;
	var $errormsg;

	/**
	 * Constructor
	 *
	 * @param string $filename  Source-Filename
	 */
	function pdf_parser($filename) {
		$this->filename = $filename;
		// mPDF 4.0
		$this->success = true;

		$this->f = @fopen($this->filename, "rb");

		if (!$this->f) {
			$this->success = false;
			$this->errormsg = sprintf("Cannot open %s !", $filename);
			return false;
		}
		// mPDF 5.0 Removed pass by reference =&
		$this->c = new pdf_context($this->f);
		// Read xref-Data
		$offset = $this->pdf_find_xref();
		if ($offset===false) {
			$this->success = false;
			$this->errormsg = sprintf("Cannot open %s !", $filename);
			return false;
		}
		$this->pdf_read_xref($this->xref, $offset);
		if ($this->success == false) { return false; }

		// Check for Encryption
		$this->getEncryption();
		if ($this->success == false) { return false; }

		// Read root
		$this->pdf_read_root();
		if ($this->success == false) { return false; }
	}

	/**
	 * Close the opened file
	 */
	function closeFile() {
		if (isset($this->f)) {
			fclose($this->f);
			unset($this->f);
		}
	}

	/**
	 * Print Error and die
	 *
	 * @param string $msg  Error-Message
	 */
	function error($msg) {
		die("<b>PDF-Parser Error:</b> ".$msg);
	}

	/**
	 * Check Trailer for Encryption
	 */
	function getEncryption() {
		if (isset($this->xref['trailer'][1]['/Encrypt'])) {
	 	// mPDF 4.0
			$this->success = false;
			$this->errormsg = sprintf("File is encrypted!");
			return false;
		}
	}

	/**
	 * Find/Return /Root
	 *
	 * @return array
	 */
	function pdf_find_root() {
		if ($this->xref['trailer'][1]['/Root'][0] != PDF_TYPE_OBJREF) {
	 	// mPDF 4.0
			$this->success = false;
			$this->errormsg = sprintf("Wrong Type of Root-Element! Must be an indirect reference");
			return false;
		}
		return $this->xref['trailer'][1]['/Root'];
	}

	/**
	 * Read the /Root
	 */
	function pdf_read_root() {
		// read root
		$root = $this->pdf_find_root();
		if ($root ===false) {
			$this->success = false;
			return false;
		}
		$this->root = $this->pdf_resolve_object($this->c, $root);
	}

	/**
	 * Find the xref-Table
	 */
	function pdf_find_xref() {
		fseek ($this->f, -min(filesize($this->filename),1500), SEEK_END);
		$data = fread($this->f, 1500);

		$pos = strlen($data) - strpos(strrev($data), strrev('startxref'));
		$data = substr($data, $pos);

		if (!preg_match('/\s*(\d+).*$/s', $data, $matches)) {
	 	// mPDF 4.0
			$this->success = false;
			$this->errormsg = sprintf("Unable to find pointer to xref table");
			return false;
		}

		return (int) $matches[1];
	}

	/**
	 * Read xref-table
	 *
	 * @param array $result Array of xref-table
	 * @param integer $offset of xref-table
	 * @param integer $start start-position in xref-table
	 * @param integer $end end-position in xref-table
	 */
	function pdf_read_xref(&$result, $offset, $start = null, $end = null) {
		if (is_null ($start) || is_null ($end)) {
			fseek($this->f, $o_pos = $offset);
			$data = trim(fgets($this->f,1024));

			if (strlen($data) == 0)
			$data = trim(fgets($this->f,1024));

			if ($data !== 'xref') {
				fseek($this->f, $o_pos);
				$data = trim(_fgets($this->f, true));
				if ($data !== 'xref') {
					if (preg_match('/(.*xref)(.*)/m', $data, $m)) { // xref 0 128 - in one line
						fseek($this->f, $o_pos+strlen($m[1]));
					} elseif (preg_match('/(x|r|e|f)+/', $data, $m)) { // correct invalid xref-pointer
						$tmpOffset = $offset-4+strlen($m[0]);
						$this->pdf_read_xref($result, $tmpOffset, $start, $end);
						return;
					} else {
						// mPDF 4.0
						$this->success = false;
						$this->errormsg = sprintf("Unable to find xref table - Maybe a Problem with 'auto_detect_line_endings'");
						return;
					}
				}
			}

			$o_pos = ftell($this->f);
			$data = explode(' ', trim(fgets($this->f,1024)));
			if (count($data) != 2) {
				fseek($this->f, $o_pos);
				$data = explode(' ', trim(_fgets($this->f, true)));
					
				if (count($data) != 2) {
					if (count($data) > 2) { // no lineending
						$n_pos = $o_pos+strlen($data[0])+strlen($data[1])+2;
						fseek($this->f, $n_pos);
					} else {
						// mPDF 4.0
						$this->success = false;
						$this->errormsg = sprintf("Unexpected header in xref table");
						return;
					}
				}
			}
			$start = $data[0];
			$end = $start + $data[1];
		}

		if (!isset($result['xref_location'])) {
			$result['xref_location'] = $offset;
		}

		if (!isset($result['max_object']) || $end > $result['max_object']) {
			$result['max_object'] = $end;
		}

		for (; $start < $end; $start++) {
			$data = ltrim(fread($this->f, 20)); // Spezifications says: 20 bytes including newlines
			$offset = substr($data, 0, 10);
			$generation = substr($data, 11, 5);

			if (!isset ($result['xref'][$start][(int) $generation])) {
				$result['xref'][$start][(int) $generation] = (int) $offset;
			}
		}

		$o_pos = ftell($this->f);
		$data = fgets($this->f,1024);
		if (strlen(trim($data)) == 0)
		$data = fgets($this->f, 1024);

		if (preg_match("/trailer/",$data)) {
			if (preg_match("/(.*trailer[ \n\r]*)/",$data,$m)) {
				fseek($this->f, $o_pos+strlen($m[1]));
			}

			// mPDF 5.0 Removed pass by reference =&
			$c = new pdf_context($this->f);
			$trailer = $this->pdf_read_value($c);
				
			if (isset($trailer[1]['/Prev'])) {
				$this->pdf_read_xref($result, $trailer[1]['/Prev'][1]);
				$result['trailer'][1] = array_merge($result['trailer'][1], $trailer[1]);
			} else {
				$result['trailer'] = $trailer;
			}
		} else {
			$data = explode(' ', trim($data));

			if (count($data) != 2) {
				fseek($this->f, $o_pos);
				$data = explode(' ', trim (_fgets ($this->f, true)));

				if (count($data) != 2) {
	 			// mPDF 4.0
					$this->success = false;
					$this->errormsg = sprintf("Unexpected data in xref table");
					return;
				}
			}

			$this->pdf_read_xref($result, null, (int) $data[0], (int) $data[0] + (int) $data[1]);
		}
	}


	/**
	 * Reads an Value
	 *
	 * @param object $c pdf_context
	 * @param string $token a Token
	 * @return mixed
	 */
	function pdf_read_value(&$c, $token = null) {
		if (is_null($token)) {
			$token = $this->pdf_read_token($c);
		}
		 
		if ($token === false) {
			return false;
		}

		switch ($token) {
			case	'<':
				// This is a hex string.
				// Read the value, then the terminator

				$pos = $c->offset;

				while(1) {

					$match = strpos ($c->buffer, '>', $pos);

					// If you can't find it, try
					// reading more data from the stream

					if ($match === false) {
						if (!$c->increase_length()) {
							return false;
						} else {
							continue;
						}
					}

					$result = substr ($c->buffer, $c->offset, $match - $c->offset);
					$c->offset = $match+1;

					return array (PDF_TYPE_HEX, $result);
				}

				break;
			case	'<<':
				// This is a dictionary.

				$result = array();

				// Recurse into this function until we reach
				// the end of the dictionary.
				while (($key = $this->pdf_read_token($c)) !== '>>') {
					if ($key === false) {
						return false;
					}
						
					if (($value =   $this->pdf_read_value($c)) === false) {
						return false;
					}
					$result[$key] = $value;
				}

				return array (PDF_TYPE_DICTIONARY, $result);

			case	'[':
				// This is an array.

				$result = array();

				// Recurse into this function until we reach
				// the end of the array.
				while (($token = $this->pdf_read_token($c)) !== ']') {
					if ($token === false) {
						return false;
					}
						
					if (($value = $this->pdf_read_value($c, $token)) === false) {
						return false;
					}
						
					$result[] = $value;
				}
				 
				return array (PDF_TYPE_ARRAY, $result);

			case	'('		:
				// This is a string

				$pos = $c->offset;

				while(1) {

					// Start by finding the next closed
					// parenthesis

					$match = strpos ($c->buffer, ')', $pos);

					// If you can't find it, try
					// reading more data from the stream

					if ($match === false) {
						if (!$c->increase_length()) {
							return false;
						} else {
							continue;
						}
					}

					// Make sure that there is no backslash
					// before the parenthesis. If there is,
					// move on. Otherwise, return the string.
					$esc = preg_match('/([\\\\]+)$/', $tmpresult = substr($c->buffer, $c->offset, $match - $c->offset), $m);

					if ($esc === 0 || strlen($m[1]) % 2 == 0) {
						$result = $tmpresult;
						$c->offset = $match + 1;
						return array (PDF_TYPE_STRING, $result);
					} else {
						$pos = $match + 1;

						if ($pos > $c->offset + $c->length) {
							$c->increase_length();
						}
					}
				}

			case "stream":
				$o_pos = ftell($c->file)-strlen($c->buffer);
				$o_offset = $c->offset;

				$c->reset($startpos = $o_pos + $o_offset);

				$e = 0; // ensure line breaks in front of the stream
				if ($c->buffer[0] == chr(10) || $c->buffer[0] == chr(13))
				$e++;
				if ($c->buffer[1] == chr(10) && $c->buffer[0] != chr(10))
				$e++;

				if ($this->actual_obj[1][1]['/Length'][0] == PDF_TYPE_OBJREF) {
					// mPDF 5.0 Removed pass by reference =&
					$tmp_c = new pdf_context($this->f);
					$tmp_length = $this->pdf_resolve_object($tmp_c,$this->actual_obj[1][1]['/Length']);
					$length = $tmp_length[1][1];
				} else {
					$length = $this->actual_obj[1][1]['/Length'][1];
				}

				if ($length > 0) {
					$c->reset($startpos+$e,$length);
					$v = $c->buffer;
				} else {
					$v = '';
				}
				$c->reset($startpos+$e+$length+9); // 9 = strlen("endstream")

				return array(PDF_TYPE_STREAM, $v);

			default	:
				if (is_numeric ($token)) {
					// A numeric token. Make sure that
					// it is not part of something else.
					if (($tok2 = $this->pdf_read_token ($c)) !== false) {
						if (is_numeric ($tok2)) {

							// Two numeric tokens in a row.
							// In this case, we're probably in
							// front of either an object reference
							// or an object specification.
							// Determine the case and return the data
							if (($tok3 = $this->pdf_read_token ($c)) !== false) {
								switch ($tok3) {
									case	'obj'	:
										return array (PDF_TYPE_OBJDEC, (int) $token, (int) $tok2);
									case	'R'		:
										return array (PDF_TYPE_OBJREF, (int) $token, (int) $tok2);
								}
								// If we get to this point, that numeric value up
								// there was just a numeric value. Push the extra
								// tokens back into the stack and return the value.
								array_push ($c->stack, $tok3);
							}
						}

						array_push ($c->stack, $tok2);
					}

					return array (PDF_TYPE_NUMERIC, $token);
				} else {

					// Just a token. Return it.
					return array (PDF_TYPE_TOKEN, $token);
				}

		}
	}

	/**
	 * Resolve an object
	 *
	 * @param object $c pdf_context
	 * @param array $obj_spec The object-data
	 * @param boolean $encapsulate Must set to true, cause the parsing and fpdi use this method only without this para
	 */
	function pdf_resolve_object(&$c, $obj_spec, $encapsulate = true) {
		// Exit if we get invalid data
		if (!is_array($obj_spec)) {
			return false;
		}

		if ($obj_spec[0] == PDF_TYPE_OBJREF) {

			// This is a reference, resolve it
			if (isset($this->xref['xref'][$obj_spec[1]][$obj_spec[2]])) {

				// Save current file position
				// This is needed if you want to resolve
				// references while you're reading another object
				// (e.g.: if you need to determine the length
				// of a stream)

				$old_pos = ftell($c->file);

				// Reposition the file pointer and
				// load the object header.

				$c->reset($this->xref['xref'][$obj_spec[1]][$obj_spec[2]]);

				$header = $this->pdf_read_value($c,null,true);

				if ($header[0] != PDF_TYPE_OBJDEC || $header[1] != $obj_spec[1] || $header[2] != $obj_spec[2]) {
	 			// mPDF 4.0
					$this->success = false;
					$this->errormsg = sprintf("Unable to find object ({$obj_spec[1]}, {$obj_spec[2]}) at expected location");
					return false;
				}

				// If we're being asked to store all the information
				// about the object, we add the object ID and generation
				// number for later use
				$this->actual_obj =& $result;
				if ($encapsulate) {
					$result = array (
					PDF_TYPE_OBJECT,
    					'obj' => $obj_spec[1],
    					'gen' => $obj_spec[2]
					);
				} else {
					$result = array();
				}

				// Now simply read the object data until
				// we encounter an end-of-object marker
				while(1) {
					$value = $this->pdf_read_value($c);
					if ($value === false || count($result) > 4) {
						// in this case the parser coudn't find an endobj so we break here
						break;
					}

					if ($value[0] == PDF_TYPE_TOKEN && $value[1] === 'endobj') {
						break;
					}

					$result[] = $value;
				}

				$c->reset($old_pos);

				if (isset($result[2][0]) && $result[2][0] == PDF_TYPE_STREAM) {
					$result[0] = PDF_TYPE_STREAM;
				}

				return $result;
			}
		} else {
			return $obj_spec;
		}
	}



	/**
	 * Reads a token from the file
	 *
	 * @param object $c pdf_context
	 * @return mixed
	 */
	function pdf_read_token(&$c)
	{
		// If there is a token available
		// on the stack, pop it out and
		// return it.

		if (count($c->stack)) {
			return array_pop($c->stack);
		}

		// Strip away any whitespace

		do {
			if (!$c->ensure_content()) {
				return false;
			}
			$c->offset += _strspn($c->buffer, " \n\r\t", $c->offset);
		} while ($c->offset >= $c->length - 1);

		// Get the first character in the stream

		$char = $c->buffer[$c->offset++];

		switch ($char) {

			case '['	:
			case ']'	:
			case '('	:
			case ')'	:

				// This is either an array or literal string
				// delimiter, Return it

				return $char;

			case '<'	:
			case '>'	:

				// This could either be a hex string or
				// dictionary delimiter. Determine the
				// appropriate case and return the token

				if ($c->buffer[$c->offset] == $char) {
					if (!$c->ensure_content()) {
						return false;
					}
					$c->offset++;
					return $char . $char;
				} else {
					return $char;
				}

			default		:

				// This is "another" type of token (probably
				// a dictionary entry or a numeric value)
				// Find the end and return it.

				if (!$c->ensure_content()) {
					return false;
				}

				while(1) {

					// Determine the length of the token

					$pos = _strcspn($c->buffer, " []<>()\r\n\t/", $c->offset);
					if ($c->offset + $pos <= $c->length - 1) {
						break;
					} else {
						// If the script reaches this point,
						// the token may span beyond the end
						// of the current buffer. Therefore,
						// we increase the size of the buffer
						// and try again--just to be safe.

						$c->increase_length();
					}
				}

				$result = substr($c->buffer, $c->offset - 1, $pos + 1);

				$c->offset += $pos;
				return $result;
		}
	}


}

?>